When I added the tonneau cover I got 1.25 mpg's more...

 

MPG is a funny subject. I tune LSx cars/trucks for a living and folks will over shoot the gas mileage to the point it's comical. Come in saying they are getting 24 now and want better on a 6.2 4x4. I check the computer and the truck is averaging 13! They change the subject.

My truck has CAI, Catback, and a tune. 6.2, 4x4. 3.73, and some really heavy 10 ply 285's on 20's. On the highway it will do 14.7-15.2 running 75, can do better on back roads at 60 but only back roads is pulling a trailer. With a mix of town/city it has been averaging 13.6-13.8. Got 10.6 pulling 28 ft enclosed trailer with racecar running 70. If I hammer it much it gets in the 12's QUICK.

 

sound more like real world numbers to me!

 

6.2 crew 4x4 342. average 16.5 with 65-70% hwy driving but my 30-35% of town driving is like that of a 16 year old. best tank to date is 21 and worst is 11. truck has 7600 miles.

 

My truck as it is is seeing 19 HWY. That's calculated by me, not the computer. The computer says 21. Its hard for me to calculate in town mileage because I'm just not in town enough to really do it, but the computer says 13. I'd venture to say it's closer to 11. Although, I do have a 3400 stall. My truck is normally around 16.8 after a mixed tank. When I drove from Temple, TX to Fort Smith, AR, I calculated 21.2... thats the best I've gotten. I run 91 octane and the 21.2 was on 93.

 

my cc 4x4 6.2 got fantastic mileage stock,headers and tune killed the fuel mileage

 

With the tune my fuel mileage is better than it was before. My average daily mixed commute returns 12mpg if driven in anger, could be better but this rig is too fun to drive. 6.2 3.73 CCSB on 33" rubber with an intake and tune with 13k miles.

 

My best average was about 16mpg over a 2500-mile one-way drive on the current setup. It was actually 15.8mpg but that was with a lot of idle time; real-world mpg was closer to 16.5 for that trip.

 

I just did a full tank of gas of 93 octane after I put my headers on, it was hand caculated to 16.8mpg (60% Highway, 40%City). This was just taking it easy driving 70 on the highway with the ocassional WOT runs. When you start hammering around on it in the city is where the MPG's go to hell in a hand basket.

On a side note, its doing better on the average with the headers than it did before. This is also before I have a tune on it (No Cats as well).

 

I had my motorcycle in the bed for a trip this weekend, about 800 miles round trip with my tailgate down and averaged a pathetic 14.5 on the highway. My old Silverado SS used to get 18 on the highway at 75-80 and I thought that was bad! Im gonna be lowering my truck 3/5 in the next 15 days so I am hoping that helps!